Webworms are everywhere

August 24, 2000

Webworms are everywhere

By TARA REILLY / Staff Writer

Chances are those hairy, yellowish-white worms crawling around in webs slung from tree branches are harmless, according to Sandy Scott, horticulture consultant with the Washington County Cooperative Extension Service.

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The insects, called fall webworms, spin webs in trees and eat leaves until they become mature larvae. The webworms then leave the nests to begin looking for sheltered places to spin cocoons and become moths.

Tree experts said they're receiving phone calls from county residents whose trees and shrubs are infested with the bugs.

"They're just all over the place," said Gary Huntsberger, plant health care monitor and inspector at Antietam Tree and Landscape in Hagerstown.

Webworms make their presence known two times a year, in May and August. The first generation of webworms, which come out in May, are rarely seen because there aren't as many hatched as the second generation worms, which are often visible hanging in trees in August, Scott said.

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The insects, which grow to be about an inch long, prefer walnut trees but can be found in more than 100 different kinds of trees.

The webworm population peaks for three to five years before disappearing until the next peak cycle, Scott said. They are in their fourth peak year.

She said that while they feed on leaves, the late-summer arriving webworms won't do much damage since the leaves are ready to fall off for the winter.

"Their bark is bigger than their bite," Scott said. "They really don't cause a lot of permanent damage to large trees."

Huntsberger said that by late summer, trees are done using their leaves to make food and are able to rebound in the spring with new buds.

So if experts say fall webworms can do little damage, then what's sparking the concerns?

"They're ugly," Scott said. "I'm not going to deny that."

She also said that once the webworms emerge from their webs, they can crawl all over homes and in sheltered areas to spin cocoons.

"When they come down they start spreading out all over the place," Scott said. "I wouldn't want a bunch of them crawling all over my house either."

Experts said the best way to kill webworms is to slice open the webs and spray insecticide inside, rather than just on the webs.

Scott advised residents not to cut off branches, since that harms the trees and prevents the branches from growing back.

"If you cut a branch off, that branch is gone forever," she said. "But they're really not a big deal. They just look bad."